This invention relates to a method of intercepting calls between two or more subscribers of a communications network to an interception manager for supporting the interception of calls between two or more subscribers of a communications network and to a service control platform for controlling services for calls in a communications network, comprising a plurality of service control points which control the provision of a service for a call when triggered for the call by a service switching point of the communications network.
National and international laws require operators of a communications network to provide mechanisms within the communications network which enable authorities (police, secret services, . . . ) to monitor telephone conversations of suspicious persons.
The invention starts from the way this problem is solved in a classical telephone network:
In the local exchange of the subscriber to be monitored, the subscriber record of the subscriber is marked, and a sort of conference connection to the authority is established. The data to be additionally determined for the respective intercepting operation are determined in the exchange by accessing the authority database, which forms part of the exchange. The entire interception mechanism is thus part of the exchange.
These existing mechanisms encounter fundamental difficulties if in a communications network, services are provided for calls using the IN architecture (IN=intelligent network): For such calls, it is usually impossible to say in advance through which exchanges and to which terminals (translation) a call will be routed.
It is the object of the invention to permit correct initiation of the monitoring for those calls for which an IN service is provided.
This object is attained by a method of intercepting calls between two or more subscribers of a communications network wherein for each of the calls, at least one of a plurality of service control points can be triggered by a service switching point of the communications network, and wherein the service control points, when triggered for a call, control the provision of a service for the call, the method further characterized in that the communications traffic between service switching points of the communications network and the service control points is routed through an interception manager central to all service control points, that the central interception manager is triggered for a call when one of the service control points is triggered for this call by one of the service switching points, that the central interception manager, when triggered for a call, monitors the communications traffic between the respective service switching point and the respective service control point for the respective call and, based on information exchanged between the respective service switching point and the respective service control point and on predefined filter criteria, determines whether the call should be intercepted or not, and that the central interception manager initiates the interception of the respective call if it determines that the call should be intercepted.
The object of the invention is further attained by an interception manager for supporting the interception of calls between two or more subscribers of a communications network, wherein the interception manager comprises a communications control unit for communication with service switching points of the communications network and for communication with a plurality of service control points which each control the provision of one service for a call when triggered for one of the calls by one of the service switching points, wherein the interception manager further comprises a control unit designed to centrally trigger the interception manager for a call when one of the service control points is triggered for this call by one of the service switching points, the interception manager further comprises at least one interception logic designed to monitor the communications traffic between the respective service switching point and the respective service control point for a call when the interception manager is triggered for this call, and to determine on the basis of the information exchanged between the service switching point and the respective service control point and on the basis of predefined filter criteria whether the call should be intercepted or not, and wherein the control unit is further designed to initiate the interception of the respective call when the at least one interception logic determines that the call should be intercepted.
Finally, the object of the invention is further attained by a service control platform for controlling services for calls in a communications network , comprising a plurality of service control points which control the provision of a service for a call when triggered for the call by a service switching point of the communications network, wherein the service control platform further comprises a central interception manager for all service control points, which is connected to the one or more service control points, the interception manager comprises a communications control unit for handling and controlling the communications traffic with service switching points of the communications network and with the service control points, the interception manager further comprises a control unit designed to centrally trigger the interception manager for a call when one of the service control points is triggered for this call by one of the service switching points, the interception manager further comprises at least one interception logic designed to monitor the communications traffic between the respective service switching point and the respective service control point for a call when the interception manager is triggered for this call, and to determine on the basis of the information exchanged between the service switching point and the respective service control point and on the basis of predefined filter criteria whether the call should be intercepted or not, and wherein the control unit is further designed to initiate the interception of the respective call when the at least one interception logic determines that the call should be intercepted.
The invention is based on the idea that a service central to all IN services is tied into the communication between the service switching points (SSPs) and the service control points (SCPs). By monitoring the signaling communication between the service switching points and the service control points, this central service determines for all IN services provided by the service control points whether the monitoring of a call is to be initiated or not. Thus, between service switching points and service control points, an intermediate layer with a function central to all service control points, an xe2x80x9cinterception managerxe2x80x9d, is introduced which decides on the initiation of the monitoring of those calls for which one or more IN services are provided.
This concept is advantageous in that correct initiation of the monitoring is made possible for calls for which an IN service is provided.
Another advantage is that the IN service logic need not be altered, so that the software of the service control points need not be modified. This considerably expedites and facilitates the creation and changing of a monitoring function, particularly if a large number of IN services are available for the communications networks:
Only a central creation/change is necessary to initiate the monitoring for a large number of IN services. If the monitoring function were integrated directly into the service control point assigned to an IN service, a creation/change of the monitoring function would have to be performed for each individual IN service, taking into account the respective service-specific functions. Accordingly, the invention is particularly suited for communications systems in which a large number of IN services are available.
A further advantage is that the service control points are not involved in the initiation of the monitoring. In the service control points, there is no information of any sort which shows that monitoring of specific subscribers is intended or currently initiated, nor is such monitoring recognizable by the service control points in any other manner. This has the advantage that this classified information is present only at a central location, namely in the interception manager. Such a central interception manager is much easier to protect than a large number of possibly spatially distributed service control points. Therefore, the solution according to the invention is also very advantageous from a security point of view. Another important aspect in this connection is that service control points and the services provided by them can also be operated by arbitrary, private service providers, which further increases the security risk.
Further advantageous aspects of the invention are defined in the subclaims.